The present invention relates to centering arrangements in general, and more particularly to a centering arrangement for centering an end wall with respect to a housing body of a hydraulic gear machine, such as a hydraulic gear pump or a hydraulic gear motor.
The basic construction of a hydraulic gear machine is so well known that it requires no detailed explanation herein. Suffice it to say that a hydraulic gear machine, which is usable either as a pump or as a motor, includes a housing body which bounds an internal chamber in which there are rotatably mounted meshing gears which define individual pressure compartments between the individual teeth at the meshing region; the housing body is open at least at one of its ends, and this end is closed by a plate-shaped end wall which may be provided with an opening for the passage of a drive shaft connected to one of the gears for joint rotation therewith between the internal chamber and the exterior of the housing constituted by the housing body and the end wall. The internal chamber is circumferentially bounded by an inner surface of the housing body.
When assembling the end wall with the housing body, it is necessary to accurately center the end wall with respect to the housing body, especially when the end wall is provided with the opening for the drive shaft. The conventional approach to this problem is to first align these two parts with one another in the required relative positions, to drill registering bores in these two parts while the same are being held in the aligned positions, and then to introduce fitting securing pins into these bores either prior to or during the assembly of the end wall with the housing body. This is a relatively expensive procedure, inasmuch as, as already mentioned before, the two parts must be first very exactly aligned with one another and the bores therein must exactly register with one another in the aligned or mounting position. The requirement for the exact pre-alignment has especially cost-raising consequences in the series production of the hydraulic gear machines.